1. Field of the Invention
The present invention relates to electrically driven optical modulators.
2. Background Information
Many applications exist within the field of photonics for electrically driven two dimensional arrays of light gates or Spatial Light Modulators (SLM"") with the ability to respond rapidly. These applications include projection display of video images, page composers for holographic data storage, optical computing including optical neural networks, multi-beam data storage, etc. Various techniques and materials have been employed to achieve these and similar devices. The materials from which SLM""are fabricated generally fall into one of several classes: micro-mechanical, liquid crystal, and electro-optic crystals and ceramics. Electro-optic crystals typically used include potassium dihydrogen phosphate (KDP), lithium niobate, lithium tantalate, ammonium dihydrogen phosphate (ADP), SrBaNiobate, BaNaNiobate, and several others.
One material typically used is PLZT, a transparent electro-optic ceramic made by sintering from a mixture of lead (P), lanthanum (L), zirconium (Z) and titanate (T). The material is fabricated in thin wafers transparent from about 400 nm throughout the visible spectrum and into the near infrared. Under an applied voltage this material exhibits either a linear Pockels or a quadratic Kerr effect, depending on the percentage of Lanthanum in the mixture which can be varied from about 7% to 12%. In both cases, the effect is voltage and temperature dependent, with operating temperatures starting from about 75xc2x0 C. requiring larger driving voltages.
Historically, devices have been built as xe2x80x9cwindowsxe2x80x9d using numerous parallel electrodes to electrically switch significant areas of material, ranging from a few square millimeters to tens of square centimeters of material. The response times of these xe2x80x9cwindowxe2x80x9d devices have typically been longer than a microsecond, which is very slow compared to other electro-optic devices, which can demonstrate nanosecond response times.
The present invention provides an optical modulation apparatus having an elongated protrusion extending from a substrate. The protrusion defines a light path and has an outer surface. A conductive element is disposed on at least a portion of the outer surface. In one embodiment of the present invention, the elongated protrusion includes a first material and the substrate includes a second material.
The present invention also provides a method for forming an optical modulation apparatus. One embodiment of the method includes: making a plurality of intersecting cuts into a substrate of an electro-optic material such that a plurality of protrusions extend from a portion of the substrate; reducing the side surfaces of each of the protrusions; coating at least a portion of the side surfaces with an electrically conductive materials; and connecting the electrically conductive material to a voltage driving element.
Additional features and benefits of the present invention will become apparent upon review of the following description.